1. Field of the Invention
This invention relates to a motor fuel additive composition and a method of preparing such an additive. More particularly, this invention relates to a motor fuel additive composition comprising: (a) a detergent component selected from the group consisting of (i) a reaction product component which is the reaction product of a substituted hydrocarbon and an amino compound, and (ii) a polybutylamine or polyisobutylamine; and (b) a fuel conditioner component comprising (i) a polar oxygenated hydrocarbon compound, and (ii) an oxygenated compatibilizing agent. This invention also relates to a method of preparing a motor fuel additive which comprises mixing the above-described reaction product and fuel conditioner components.
2. Description of the Related Art
Incomplete combustion of hydrocarbonaceous motor fuels in an internal combustion engine is a common problem which generally results in the formation and accumulation of carbon and other deposits in various places, including the fuel inlet system. Significant efforts have previously been undertaken to develop fuel additives to reduce or inhibit deposit formation in the engine fuel inlet system. Early so called xe2x80x9cfirst generationxe2x80x9d additives directed primarily to cleaning carburetors and injectors include low molecular weight amine derivatives such as fatty amines, amides, amido amines and imidazolines. Later developed so-called xe2x80x9csecond generationxe2x80x9d additives, directed to cleaning inlet valves as well as carburetors and injectors, have been based primarily on polyolefinic structures, typically polyisobutenes and their derivatives. For example, the use of polybutene succinimides as fuel additives has been disclosed in U.S. Pat. No. 3,443,918 (Kautsky et al.) and U.S. Pat. No. 3,172,892 (LeSeur et al.); the use of polybutene amines as fuel additives has been disclosed in U.S. Pat. No. 3,438,757 (Honnen et al.); the use of a fuel system only cleaning composition based on an oxy compound and a dispersant has been disclosed in U.S. Pat. No. 3,658,494 (Dorer, Jr.).
For effective deposit control, it has been customary to use such additives in conjunction with petroleum based or synthetic carrier oils. Petroleum based oils useful in this respect include naphthenic and paraffinic base stock oils of relatively high viscosity, including so-called Solvent Neutral Oils such as SNO-500 and SNO-600, as well as so-called top cylinder oils and the like. Synthetic oils which have been employed include low molecular weight polypropylenes and polyisobutylenes, as well as polyalkyleneoxides.
Although the above-described additives have been found effective in reducing deposits in the fuel intake system, the increased use of these additives, particularly the second generation additives, in motor fuels has been found to have led to an increase in combustion chamber deposit formation. The presence of deposits in the combustion chamber seriously reduces engine operating efficiency for several reasons. First, deposit accumulation within the combustion chamber inhibits heat transfer between the chamber and the engine cooling system. This leads to higher temperatures within the combustion chamber, resulting in increases in the end gas temperature of the incoming charge. Consequently, end gas auto-ignition occurs, which causes engine knock. In addition, the accumulation of deposits within the combustion chamber reduces the volume of the combustion zone, causing a higher than design compression ratio in the engine. This, in turn, also results in serious engine knocking. A knocking engine does not effectively utilize the energy of combustion. Moreover, a prolonged period of engine knocking will cause stress fatigue and wear in vital parts of the engine. The above-described phenomenon is characteristic of gasoline-powered engines. It is usually overcome by employing a higher-octane gasoline for powering the engine, and hence has become known as engine octane requirement increase (ORI) phenomenon.
The reference SAE paper number 941889, xe2x80x9cMechanism of Combustion Chamber Deposit Formationxe2x80x9d, Daly, Bannon, Fog and Harold, all of Lubrizol Corp., Oct. 17-20, 1994, teaches a means of determining the mechanism by which CCD are formed, and their association with the phenomenon of octane requirement increase (ORI).
The reference SAE paper number 941892, xe2x80x9cA Physical Mechanism for Deopsit Formation in a Combustion Chamberxe2x80x9d, Cheng, of General Motors Crop., Oct. 17-20 1994, teaches another mechanism for the deposit of CCD in internal combustion engines. It further teaches that it has been universally recognized that combustion chamber deposits are undesirable, but also unavoidable, products of engine combustion. Ever since the inception of internal combustion engines, we have managed to live with combustion chamber deposits, although we really would like to get rid of them, if only we knew how. The reference also teaches that combustion chamber deposits seem to have some beneficial.effects on fuel efficiency.
The reference SAE paper number 941893, xe2x80x9cEffects of Gasoline and Gasoline Detergents on Combustion Chamber Deposit Formationxe2x80x9d, Takei, Uehara, Hoshi, and Okada, all of Toyota Motor Corp., Oct. 17-20, 1994, teaches that the increase in CCD caused by fuel detergent additives and finds that many detergent additives currently available do in fact increase CCD.
The reference xe2x80x9cFinal Rule Interim Requirements for Deposit Control Gasoline Additives: Regulatory Textxe2x80x9d, U.S. EPA, Oct. 14, 1994, teaches that the accumulation of CCD resulting from the use of detergent additives used to control fuel system cleanliness is of grave concern and without solution.
In view of the foregoing, it would clearly be advantageous to employ an additive in motor fuel compositions which reduces deposits in engine fuel intake systems and also avoids the formation of deposits in engine combustion chambers, thereby reducing or at least modifying the composition of deposits which tend to cause engine ORI.
It is an object of this invention to provide a motor fuel additive, which is useful in preventing both fuel intake system deposit formation-and combustion chamber deposit formation. It is a feature of this invention that the additive comprises a detergent component and a fuel conditioner component, which synergistically interact to reduce both fuel intake system and combustion chamber deposit formation. It is an advantage of this invention that it both reduces deposit formation in engine fuel intake systems and ORI associated with combustion chamber deposit formation.
It is another object of this invention to provide a method for preparing a motor fuel additive which reduces deposits in engine fuel intake systems and also reduces the formation of deposits in engine combustion chambers, thereby reducing engine ORI. It is another feature of this invention that such an additive is prepared by mixing a detergent component and a fuel conditioner component which synergistically interact to reduce both fuel intake system deposit formation and ORI associated with combustion chamber deposit formation.
The motor fuel additive composition of this invention comprises a mixture of:
(a) from about 5 to about 50 weight percent, based upon the total weight of the additive, of a detergent component selected from the group consisting of
(i) a reaction product of:
(A) a substituted hydrocarbon of the formula
R1xe2x80x94Xxe2x80x83xe2x80x83(I)
xe2x80x83wherein R1 is a hydrocarbyl radical having a molecular weight in the range of 150 to about 10,000, and X is selected from the group consisting of halogens, succinic anhydride and succinic dibasic acid, and
(B) an amino compound of the formula
Hxe2x80x94(NHxe2x80x94(A)m)nxe2x80x94Yxe2x80x94R2xe2x80x83xe2x80x83(II)
xe2x80x83wherein Y is O or NR5, R5 being H or a hydrocarbyl radical having 1-30 carbon atoms; A is a straight chain or branched chain alkylene radical having 1-30 carbon atoms; m has a value in the range of 1-15; n has a value in the range of 0-6; and R2 is selected from the group consisting of H, a hydrocarbyl radical having a molecular weight in the range of 15 to about 10,000, and a homopolymeric or heteropolymeric polyoxyalkylene radical of the formula
R3xe2x80x94((Q)a(T)b(Z)c)dxe2x80x94xe2x80x83xe2x80x83(III)
wherein R3 is H or a hydrocarbyl radical having 1-30 carbon atoms, Q, T, and Z are polyoxyalkylene moieties having 1-6 carbon atoms, a, b and c each have values ranging from 0-30, and d has a value in the range of 1-50, and
(ii) a polybutylamine or polyisobutylamine of the formula 
xe2x80x83where R11 is a polybutyl or polyisobutyl radical derived from isobutene and up to 20% by weight of n-butene and R12 and R13 are identical or different and are each hydrogen, an aliphatic or aromatic hydrocarbon, a primary or secondary, aromatic or aliphatic aminoalkylene radical or polyaminoalkylene radical, a polyoxyalkylene radical or a heteroaryl or heterocyclyl radical, or, together with the nitrogen atom to which they are bonded, form a ring in which further hetero atoms may be present; and
(b) a fuel conditioner component comprising:
(i) from about 2 to about 50 weight percent, based upon the total weight of the additive, of a polar oxygenated hydrocarbon having an average molecular weight in the range of about 200 to about 500, an acid number in the range of about 25 to about 175, and a saponification number in the range of about 30 to about 250, and
(ii) from about 2 to about 50 weight percent, based upon the total of the additive, of an oxygenated compatibilizing agent having a solubility parameter in the range of about 7.0 to about 14.0 and moderate to strong hydrogen-bonding capacity.
The fuel conditioner component may additionally comprise a hydrophilic separant such as a glycol monoether, and an aromatic hydrocarbon such as xylene or a xylene. The additive composition may additionally comprise a carrier oil or fluidizer.
This invention is also directed to a method of preparing the motor fuel additive of this invention, which comprises mixing the detergent and fuel conditioner components to obtain the additive. The motor fuel additive of this invention is advantageous in that the detergent and fuel conditioner components synergistically interact when employed in a fuel composition to reduce both fuel intake system deposit formation, thereby improving engine performance, and combustion chamber deposit formation, thereby reducing engine ORI.